X17online has the FIRST PHOTOS of Lindsay Lohan in rehab at the Betty Ford Center in Rancho Mirage, CA -- shot today just after noon, we saw the actress walking toward the meeting hall with a counselor from the facility looking upbeat and happy.

A photographer on the scene tells us: "Lindsay was chatting with the woman who accompanied her and she looked like she was feeling positive and in a good mood. She didn't dress in casual clinical clothes either -- she was her usual fashionable self in knee-high boots and a sleeveless dress. It's really hot out there in the desert."

Lindsay entered the legendary drug and alcohol institution yesterday, likely at the behest of her new handler Lou Taylor and her mom Dina. It's believed she chose a more serious, non-profit facility, as opposed to a posh, expensive Malibu rehab, in hopes of proving to Judge Elden Fox she's serious about getting clean.

Betty Ford's track record is great -- it's methods are said to have resulted in an extremely high success rate for various celebs who've spent time there as well as all of the "regular" people who've sought help from the preeminent treatment facility.

Lindsay certainly looks great in the pictures; imagine how great she'll look (and feel) if she sticks it out for 30 days or more. Chin up, Linds, and best of luck!

Do you think Lindsay will make it until her October 22nd hearing or will she ditch her desert digs and hit Hollywood before the end of 30 days?